Historic July 5 dust storm engulfing downtown Phoenix. The dust may have contained fungus spores from the desert floor that can cause a respiratory infection.

An Arizona health expert expressed concern that the two huge clouds of dust that tumbled over Phoenix this month could trigger an increase in the number of valley fever cases during the summer.

John Galgiani, director of the Valley Fever Center for Excellence at the University of Arizona College of Medicine, said the dust storms probably sent airborne the spores of the fungus that cause the respiratory infection, allowing them to be more easily inhaled.

“People living in Phoenix and the surrounding areas should know about this risk and seek medical attention if they develop symptoms of pneumonia,” Galgiani said in a statement.

He added that early diagnosis and treatment can drastically reduce the severity of the infections.

Arizona accounts for two-thirds of the cases of valley fever contracted annually in the United States.